Galaxy Helios Light Speed Chiller Manager Sequence of Operation

This set of vocabulary flashcards covers the operational sequences, equipment components, and control setpoints for the Galaxy Helios Light Speed chiller management and adiabatic cooling systems.

Facility Chilled Water (FCW) System

A variable primary flow system consisting of 95 air-cooled chiller skids, 11 chiller managers, 36 CDU groups, 124 CRAH units, and other components designed for continuous 24/7 operation.

Chiller Manager

One of 11 units that monitors between 6 and 9 chillers, staging them up or down by commanding the chillers and their respective primary pumps.

Staging Up Criteria

Conditions including average chiller load > $60\%$ for more than $2\,minutes$, differential pressure $3\,PSI$ less than setpoint, or discharge temperature $2^{\circ}F$ greater than setpoint.

Staging Down Criteria

Conditions including average chiller load < $40\%$ for more than $10\,minutes$, differential pressure within $2\,PSI$ of setpoint, and discharge temperature within $1^{\circ}F$ of setpoint.

Plant Primary Chiller Manager

The component that averages all plant differential pressure sensors to send a common pump speed command to all operating chiller managers.

Chiller Skid Components

Includes an air-cooled chiller, a facility chilled water pump on a VFD, an air separator, manual isolation valves, and an adiabatic cooling skid.

FCWS-T-SPT

The adjustable Facility Chilled Water Supply Temperature Set Point, which has a default value of $60^{\circ}F$.

FCWS-DP-SP

The Facility Chilled Water System Differential Pressure Set Point, used to ramp all primary pumps together, with a default value of $20\,PSI$.

Loss of Communication Preset Speed

The default speed of $75\%$ that a pump will maintain if it or the chiller loses communication with the chiller manager.

FCW Minimum Flow Setpoint

The greater of the speed required to meet the chiller minimum flow setpoint and $20\,Hz$.

Adiabatic System

A system sized to provide $3.75\,GPM$ of water to each of the two refrigeration circuits to lower the incoming air to the condenser coils.

Adiabatic Enablement Temperature

The adjustable threshold where the entering air temperature for the condenser coil must be greater than $117^{\circ}F$.

Adiabatic Enablement Humidity

The adjustable threshold where the ambient relative humidity must be less than $80\%\,RH$.

Adiabatic Purge Sequence

A sequence triggered if the system hasn't run in twelve hours, running high pressure pumps for $5\,seconds$ to prevent water stagnation.

Adiabatic Winter Maintenance

The requirement that each adiabatic skid must be drained during winter months to prevent freezing.